Typewriting machine



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63 R. D. ET AL TYPEWRITING MACHINE Filed Nov. 29, 1940 2 Sheets-Sheet 2 7 m' T N11,: m

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Patented Apr. 6, 1943 TYPEWRITING MACHINE Ronald D. Dodge, Rochester, and Jess Earl Wood,

Odessa, N. Y., assignors to International Business Machines Corporation, New York, N. Y., a corporation of New York Application November 29, 1940, Serial No. 367,710

12 Claims.

the present invention by combining the usual type guide and anvil in one piece for attachment as a unit to the segment and by changing the shapes of the anvil and guide.

Other objects of the invention will be pointed 1 out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings: I

Fig. 1 is a front elevation of the segment and anvil with a single type bar shown in the operated position.

Fig. 2 is a vertical section on the line 2-2 of Fig. 1.

Fig. 3 is a side view of a type bar from the right hand group on the segment with reference to Fig. 1.

Fig. 4 is an edgewise view of the type bar shown in Fig. 3.

Fig. 5 is a side view of a type bar from the left hand group with reference to Fig. 1.

Fig. 6 is an edgewise view of the type bar shown in Fig. 5.

Fig. 7 is a plan view of the combined type guide and anvil,.separate from the segment.

Fig. 8 is a front view of the combined type guide and anvil.

Fig. 9 is a front view of the segment with type guide, anvil, and type bars removed.

The present invention is concerned with improvements in machines which employ the well known wire segment, which consists of a segment shaped casting along the curved edge of which is disposed a curved wire which acts as a pivot for the type bars. The type bars are usually located on the curved pivot wire in slots cut in the segment in a direction normal tothe pivot wire. The slots in the ordinary segment, if extended toward the platen, would converge at a point close to the point at which the impression of the type is made, and the curved pivot wire, as well as the curved edge of the segment,

' single die with the result they are all the same length prior to the final shaping which bends the ends of the'type bar adjacent the type elements varying degrees to suit the position of the type bar in the segment. The end type bars necessarily must be very sharply bent because the type, when it strikes the printing point, must be vertical with both characters in vertical alignment. The type bars near the center 01. the machine may not be bent at all or very slightly, the extent varying in difierent machines. The eifect of bending the type bars varying degrees is to change their effective length. When they operate at high speed there is considerable difference in the intensity of the impressions made 'by the type bars at the ends of the segment, which are most sharply bent, and the ones in the middle which may not be bent at all.

In Figs. 3 to 6, there is shown two different specimen type bar blanks which in their general shape may be considered as conventional. The type bar blank designated I0 in Figs. 3 and 4 is one of the group which is located in the right hand half of the segment and is shown as bent at its upper end at an angle A which will depend upon the position of the type bar in the segment. The type bar blank at the extreme right hand end of the segment may be bent so that the angle A is approximately whereas the type bar at the middle of the segment (Fig. 1) may not be bent at all' or at least only a little more than 1.

In Figs. 5 and 6, is shown a type bar blank se lected from the left hand group on the segment which blank likewise has its head bent in the opposite direction at an angle A which will depend upon the position the type bar occupies in the segment.

In Fig. 9 there is shown a view of a segment l2 which is conventional in respect to the manner in which the type bars are mounted thereon and the disposition of the slots and pivot wire. In Figs. 1 and 2 a single type bar ll of the left hand group is shown pivoted on the segment I2 by means of the pivot wire l3 which is laid in one of th two middle slots IZa in the rear face of the segment. It is plain thatthe type bar II in Fig. 1 has very little tendency to twist on its 1ongitudlnal axis due to the fact that the head of the type bar is very slightly bent, a fact which is not noticeable in Fig. 1, whereby the slightly offset mass of the type element Ila has relatively little twisting force .on the type bar.

A type bar which is bent as much as those showh in solid lines in Figs. 4 and 6 does, however, have a tendency to twist, owing to the fact that the mass comprising the type element Ha (Fig. 2) is offset with respect to the longitudinal axis of the type bar with the result that when I the type bar is operated, particularly when operated by power mechanism, the type bar tends to straighten out, due to centrifugal force and. to twist due to the inertia of the offset head of the type bar with its type element. Furthermore, when the impact with the platen occurs, the re action of the platen which finally arrests the head of the type bar also may have a tendency to twist the type bar since the force of reaction, as will be seen in Figs. 4 and 6, will be applied at a point outside of the longitudinal axis of the type bars, thereby tending to twist the type bar on its pivot or about its longitudinal axis. Usually, however, the type bar first strikes the anvil and the remainder of the stroke of the head of the type bar is by a whipping action, the type bar flexing about the anvil as a pivot to the extent necessary to produce the impression. Since the further progress of the type element is independ out upon the kinetic energy stored in the head of the type bar, there is a further tendency to twist since the ofiset mass of the type element owing to inertia tends to continue toward the platen, thereby twisting the type bar. In some cases, where there is a very thick pack of work sheets, as when making carbon copies, the characters on the type element may actually strike the work sheets before striking the anvil, whereby one or both of the effects described above always is produced. Since the type characters IIb (Fig. 2) are located difierent distances from the point of the bend in the head of the type bar, the twisting effect upon impact is diiferent for the two type elements owing to the fact that the leverage exerted in the case of the upper character striking is greater than when the lower type character strikes. Since the mechanical leverage ratio is about 2:1, it will be seen that there will be considerable difference between impressions made by the upper type characters and the lower type characters of those type bars which are sharply bent.

In the well known Electromatic typewriter, the upper type character I Ib (Fig. 2) is the upper case type and the lower type character is the lower case type. Consequently, when the upper case character is being printed, the tendency of the type bar to twist may be greater than when the lower case character is being printed.

The anvil usually consists of a rib formed in the segment and acts as a stop for the type bar which takes effect before the actual contact of the type element with the ribbon is made, with the result that the actual impressions of the characters on the paper are effected by a whipping action of the type bar. The anvil is usually located about half way between the pivot wire for the type bar and the printing point, with the result that the impression of the characters on the work sheet is effected by flexing each type bar at substantially its midpoint.- Just prior to impact, the center type bars, being only slightly bent, pivot about the anvil in a plane which is very nearly coincident with the plane in which the type bar moves. On the other hand, the heads of the end type bars are so sharply bent that, when they strike the anvil, there is not only a pivotal movement about the anvil in the oblique plane .of movement of the type bar, but there is also a tilting pivoting movementof the type element in a vertical plane about a horizontal axis which passes through the bend in the type bar and parallel with the platen. Because of this tilting, there is a tendency for the lower case character to print too low and the upper case to print too high in varying degrees depending upon their distance from the middle bars of the segment, those at the ends tilting the most and those near the middle the least or not at all. This tilting action not only affects the alignment of the characters but also affects the intensity of the impression because the upper and lower portions of the characters do not exert equal pressure upon the work sheet due to the tilting action and to diiTerences in the areas of the type faces with the result that the impressions are not even.

It has been discovered that the difiiculties explained above may be overcome by combining the anvil with the type guide and changing the shape of both the anvil and the type guide. As most clearly shown in Figs. 1, 7, and 8 there is provided a combination anvil and type guide designated I5 which it is preferred to form of a steel plate and which is attached to the front face of the segment by means of four screws I6 which pass through holes I! in the plate. The plate I5 is formed with a raised portion or rib I8 which acts as an anvil against which the type bars I0, II may strike. The plate I5 is also formed with an arm or extension I 9 having lugs 20 at its upper end bent at right angles to extension I9 and shaped to form a type guide having the throat 2|. Extension I9 also serves as a guide for the usual ribbon vibrator (not shown).

It will be noted in Figs. 1 and 8 that the anvil I8 is U-shapecl instead of being, as would ordinarily be the case, an arc of a circle concentric with pivot wire I3. The portion of the anvil near the center of the segment is an arc of a circle of considerably smaller radius than ordinarily is the case and has its center at about the point P, Fig. 8. The point P is located a considerable distance nearer the pivot wire I3 than in ordinary segments in which the center of curvature of the anvil is at the same point as the center of curvature of the are formed by pivot wire I3. Portions of the anvil at the extreme ends extend substantially straight upwardly.

With the anvil I8 so constructed, the edges of the type bars will contact the anvil I8 variable distances from the pivot wire I3 and the printing point, measured along the lengths of the type bars, those type bars at the extreme ends of the segment contacting the anvil at the greatest distance from the wire. It has been found that with the anvil shown in Figs. 1 and 8, the impressions produced by the end type bars are just as even and as heavy as impressions produced by the type bars around the middle of the segment.

It is desirable that a certain amount of adjust- 1 I I for screws I6 are made slightly larger than necessary whereby a certain amount of pivotal movement of the plate I! and pin 22 can be made.

It has been found that to utilize the principle of varying the point of engagement of the type bars with the anvil to best advantage requires that a constant relationship be maintained between the anvil and the type guide, and for that reason it is desirable that the two elements be combined in one piece to prevent change in the relationship of the guide and the anvil. It is also desirable that the type head be kept under the influence of the guide as close to the platen as practical in order to utilize the invention to the best advantage, and for this purpose the extension I9, below lugs 20, is bent as shown at 25 (Figs. '1 and 8) to bring the rear end of throat 2| as close to the platen as possible. This reduces to a minimum any possible twisting effect that the type element might have about a vertical axis passing through the throat 2i due to the tendency of the head of the bar to twist. Thus the change in the shape of the type guide cooperates materially with the change in the shape of the anvil to produce improved results.

It will be noted with reference to Fig. 1 that the slots in the segment I2 if prolonged will intersect in a common point or focus a short distance below the type element HA and, with the usual mounting position of the segment in the machine, a normal drawn to the pivot wire I3 at its midpoint will pass through this focus and also through the printing point and will be substantially at right angles to the platen or rather in a plane which is at right angles to the platen. The type bars of each group and the slots l2a are symmetrically located on the segment with respect to this normal, whereby the end type bars in striking make the same angle to a vertical plane passing through the normal at right angles to the platen. Point P (Fig. 8) lies in this normal. In order to avoid interference between the heads of the type bars which are bent sharply, it is necessary that the slots I20. be spaced further apart near the ends of the segment than at the middle. In some machines, the slots in the segment may not converge to a common focus but usually two symmetrically located slots will always converge at a point in the normal to the pivot wire IS. The type guide should be located so that the center of the throat in the type guide coincides with the normal to the pivot wire and the two branches of the semi-circular anvil most commonly used should also be symmetrical with respect to the normal in an ideal machine. The pivot wire l3 does not necessarily have to conform to a true are of a circle but in the present case this has been assumed for convenience. It is not the intention, therefore, to be limited to the specific shape of the segment, the spacing and arrangement of the slots, or the specific manner of mounting the type bars.

While there has been shown and described and pointed out the fundamental novel features of the, invention as applied to a single embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. .It is the intention therefore to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In a typewriting machine of the type wherein the type bars are mounted with their pivots in an arc and have types swinging in an arc, to impact a work sheet at a common printing point and wherein the type bars, intermediate the typ s and their pivots, strike and are flexed by an anvil which arrests the type bars prior to impact of the types at the printing point to effect said impact of the types by flexure of the type bars at the anvil contacting portions of the type bars, an anvil shaped to contact the type bars at the center of said are closer to said are than the 2 in the type bars are mounted with their pivots in an arc and have types swinging in an arc to impact a work sheet at a common printing point and wherein the type bars, intermediate the types and their pivots, strike and are flexed by an anvil which arrests the type bars prior to impact of the types at the printing point to effect said impact of the types by flexure of the type bars at the anvil contacting portions of the type bars, a U-shaped anvil disposed to intercept and flex certain type bars farther from their pivots and nearer the printing point than other type bars. i

3. In a typewriting machine of the type wherein the type bars are mounted with their pivots in an arc and have types swinging in an arc to impact a Work sheet at a common printing point and wherein the type bars intermediate the types and their pivots strike and are flexed by an anvil which arrests the type bars prior to impact of the types at the printing point to effect said impact by flexure of the type bars at the anvil contacting portions of the type bars, a U-shaped anvil disposed with the branches of the U in positions to intercept and flex the end type bars farther from their pivots and nearer the printing point than the type bars intermediate the ends of said are.

4. In combination with a segment having a curved edge, a series of type bars having pivots mounted along the curved edge in slots in said segment and having a common printing point, said slots if prolonged toward the printing point substantially converging to a point close to the printing point; and a combined anvil and type guide mounted on such segment, said type guide being located close to the printing point so as to guide any operated type bar to printing point, and said anvil being so shaped that the type bar contacting portions thereof are located varying distances between the pivot points of the type bars and the printing point.

5. In a typewriting machine of the type wherein the type bars are mounted with their pivots in an arc and have types swinging in an arc to impact a work sheet at a common printing point and wherein the type bars, intermediate the types and their pivots, strike and are flexed by an anvil which arrests the type bar's prior to impact of the types at the printing point to effect'said impact by flexure of the type bars at the anvil contacting portions of the type bars, an anvil shaped to arrest and flex the end type bars a minimum distance from the printing point and the central type bars a maximum distance from the printing point and to intercept and flex those type bars intermediate the end and control type bars progressively greater distances from the printing point in a range from the minimum of the end type bars to the maximum of the central type bars.

6. In combination with a series of type bars having a common printing point, a segment having a curved edge and guide slots in said edge extending normal to the curved edge, means to pivotally support said series of type bars in. said slots at a substantially constant distance from the printing point, and a plate formed with a type guide between th printing point and the pivotal supporting means and with an anvil portion curved to arrest the type bars varying distances from the printing point measured along the lengths of the type bars.

7. In combination with a series of type bars, means to pivotally support said series of type bars in an arc of a circle for movement to a printing point located close to the center of curvature of such are, an anvil arranged to be contacted by said type bars just prior to ciiecting an impression, said anvil being so shaped that is contacted by the type bars located near the middle of the are at points nearer said] are than by the type bars at the ends of the arc, means to p votally adjustably mount the anvil between the middle of the arc and the printing point and located in a l ne normal to said are drawn through the center of the arc. and means to secure the anvil in pivotally adjusted position 8. In combination with a series of type bars having a common printing point, a curved type bar support, a U-shaped anvil having the curved portion of the U connecting the branches located in a position to be engaged by the middle type bars and the branches of the U located to be engaged by the end type bars of the group, means to pivotally adjustably mount the anvil on the type bar support close to the center of the curved portion of the U to enable the branches of the U to be adjustably positioned between the printing point and the ends of the are formed by the curve of the type bar support, and means to secure the anvil in adjusted position.

9. In combination with a series of type bars having a common printing point, means to pivotally mount said type bars in an arc with reference to the printing point of the type bars, an anvil with substantially all of its type bar contacting portion having the shape of an arc with a smaller radius of curvature than the first arc and with a center of curvature located between the first arc and the center of curvature of such are, means to pivotally mount the anvil between the printing point and the first arc and in a line normal to the first are at the middle of the first are, and means to secure the anvil in adjusted position.

10. In combination, a segment having a curved edge, a series of type bars pivotally mounted along the curved edge in slots cut in said segment and having a common printing point, said slots if prolonged toward the printing point substantially converging to a point close to the printing point, a combined anvil and type guide mounted on such segment, said type guide being located close to the printing point so as to guide any operated type bar to the printing point, said anvil being so shaped that the type bar contacting portions thereof are located varying distances between the pivot points of the type bars and the printing point; means to pivotally adjustably mount the anvil and type guide on said segment in a line draw through the center of the arc forming the curved edge of the segment and the print- 'ing point, and means to secure the anvil in adjusted position.

11. In combination with a segment having a curved edge, a pivot wire mounted concentric with the curved edge; a series of type bars mounted on the pivot wire and having a common printing point, the longitudinal axes of such type bars when operated passing through a common focal point for all of the type bars; an anvil shaped to intercept those type bars at the middle of the segment at points nearer the pivot Wire than those which the anvil intercepts the type bars located at the ends of the pivot wire; a type guide movable with said anvil, and means to adjustably secure the anvil on said segment to swing about a center located between the printing point and the center of the pivot wire to enable the position of the type'guide and the ends of the anvil to be adjusted in relation to the ends of the pivot wire to produce a symmetrical impact condition of the anvil 12. In combination with a series of type bars having a common printing point, a segment having a curved edge and guide slots in said edge extending normal thereto, means to pivotally support said series of type bars in said slots at a substantially constant distance from the printing point, a plate formed with a type guide between the printing point and the pivotal supporting means and with an anvil portion curved to arrest the type bars varying distances from the printing point measured along the lengths of the type bars. means to pivotally connect said plate with said segment at a point between the pivotal supporting means and the printing point for adjustment of the branches of the anvil portion and the type guide in relation to the printing point, and means to secure the plate in its adjusted position.

RONALD D. DODGE. JESS EARL WOOD. 

